pub fn new_birthday_probability(n: u32) -> f64 {
    if n < 2 {
        return 0.0;
    }

    let all_day = 365;
    let mut probability = 1.0;

    for i in 0..n {
        probability *= (all_day - i) as f64 / all_day as f64;
    }

    1.0 - probability
}
